Cyan color formers capable of yielding fine grain images



Patented Nov. 14, 1950 2,530,349 cYAN-coLoR 'FoRMERs CAPABLE OF"YIELDING FINE GRAIN IMAGES Winfred C. Craig, Westfield, N. J assignor toGeneral Aniline & Film Corporation, New York, N. Y., a corporation ofDelaware No Drawing. Application April 30, 1947, Serial No. 745,113

The present invention relates to cyan color formers and moreparticularly to such color formers which upon color forming developmentare capable of yielding quinoneimine dyes of excellent spectralproperties andexceedingly fine grain.

In USP 2,373,821 there is disclosed cyan color formers comprising anaromatic hydroxy compound containing in its molecule a S-memberedheterocyclic nucleus, such as, a benzothiazole, benzoxazole orbenzimidazole. Specific reference is made in the patent to thepreparation of -2-(.2'-.- (l'-hydroxy) naphthyl) benzimidazole byheating the condensation product from I-hYdI'OXYfZ- naphthoic acid andO-phenylenediamine to split off water.

The patentee points out that the color formers disclosed therein areparticularly characterized by the fact that the dyestufis obtainedtherefrom exhibit an especially high absorption in the short waveinfra-red, making the color formers emi- Claims.

the solubilizing' substituent the compounds are readily dispersedinphotographic emulsions and are non-migratoryonce they have beenincorporated therein. Said color formers, their use in photographicemulsions and the processing of such emulsions to cyan dye images,constitute the purposes and objects of the present invention.

nently suitable for use in' the negative-positive process. The patenteealso asserts that owing to the high absorption in the long wave red ofthe quinoneimine dyestuffs produced from the color formers, the color.formers are also utilizable in the formation of sound records. I

While the color formersdescribed in the patent possess the propertiesattributable thereto by the patentee, they nevertheless suffer fromthevery serious disadvantage that the dyestuff. images which they yieldupon color forming development are of relatively coarse grain. For thisreason, such color formers have little or no utility in color film ofsmall size, particularly 8 mm. film which for proper reproductionrequires fine grained mages, particularly as regards the cyan or keyimage.

I have now discovered a class of cyan color formers which comprises ahydroxy aromatic radical, the carbon atom in ortho-position to saidhydroxyl group bein directly linked to the carbon atom in the 2-positionof a benzimidazole nucleus,-said benzimidazole nucleus being substitutedon the nitrogen atom in the l-position by a long aliphatic chain and inthe fused-on benzo radical by a Water solubilizing group. It -has beenascertained that compounds so constituted, when employed as colorformers in photographic emulsions, not only possess the properties ofthe color formers described in the abovementioned patent but also havethe additional very desirable characteristics of yielding cyan dyeimages on color development which have excellent spectral properties andan exceedingly fine grain. For this reason, the compoundsareparticularly adapted for utilization in the redsensitive layer of smallThe color formers contemplatedherein are depicted' by the following"structural- ,formula:

wherein R1 is a hydroxy aromatic radical, the hydroxy group beingdirectly linked to a nuclear carbon atom, such as, hydroxy naphthyl,hydroxy phenyl and the like and such radicals substituted by halogen, i.e., chlorine, bromine and the like, sulfo, carboxy, lower alkyl, i. e.,alkyl containing up to five carbon atoms, such as, methyl, ethyl,propyl, butyl and amyl, and lower alkoxy, the alkyl radical of which isas above, R2 is a long aliphatic chain containing at least ten carbonatoms, such as,,decyl, lauryl, oleyl,'octadecy1 and the like and R3 is aWatersolubilizing group, such as, sulfo, carboxy, hydroxy, hydroxypoly-ethenoxy ether radical and the like. I

The new class of .color formers is obtained by two reactions, the firstinvolving the condensation of a 1-hydroXy-2-aroyl chloride with anorthophenylenediamine of the following formula:

wherein R2 and Rs have the values given above with the eliminationoflhydrogen chloride, and

the second involving the ring closure of thecqndensation product withelimination of water. The condensation reaction is generally effected byheating the components in an inert diluent, such as, benzene, toluene orthe like to a temperature ranging from about to 150 C. in the presenceof an acid binding agent, such as, pyridine, a-PiC- oline, quinoline andthe like. The ring closure reaction is generally effected by heating thecondensation product-to a temperature ranging from about to C; inthepresence of awater binding agent, such as, acetic anhydride, glacialacetic acid and the like. The product resulting from ring closure afterisolation from the reaction mixture may be purified by dissolving it ina hot mixture of benzene and alcohol and recrystallizing the productfrom such solution.

The following are illustrative of color formers embraced by the aboveclass:

(1) 1 octadecyl-2-(2'-(1'-hydroxy) naphthyl) benzimidazole-5-sulfonicacid.

i\ OH C HSO (2) 1-octadecy1-2- (2'- (1-hydroxy 4' chloro) naphthyl)benzimidazole-S-sulfonic acid.

isHav z r on v U HSOa N/ (a) l-octadecyl-Z-(2'-(1-hydroxy 4' sulfo)naphthyl) benzimidazole-5-sulfom'c acid.

U HSOs- N/ (4) l-oleyl 2 (2' (1' hydroxy) naphthyl)benzimidazole-S-sulfonic acid.

OuHu

- 1li\ on I I HSO (5) l-oleyl 2 (2'-(1' hydroxy 4' chloro) naphthyl)bezizimidazole-S-sulionic acid.

iaHu i 0.. I a 0 (1) nsm- (6) 1 -octadecyl-2-(2'-(1'-hydroxy-6'-methyl)phenyl) benzimidazole-B-Sulfonic acid.

T It 031 I 1 7 V O \CUCH: Hso.

(7) l-lauryl- 2*(2 (1' hydroxy) naphthyD- benzimidazo1e-5-sulfonic acid.

(8) 1-octadecyl-2(2-(1'-hydroxy-6-methoxy) phenyl)benzimidazole-5-sulfonic acid.

GiaHaz it on G- can; no: N/

(9) l-oleyl 2 (2' (1 hydroxy) naphthyl) benzimidazole-5-carboxylic acid.

CmHas /I l\ on Hooo O N/ The color formers are incorporatedinphotographic emulsions in the customary manner as by dissolving themin water or aqueous alkaline solutions and adding the solution toagelatino silver halide emulsion. The emulsions may be utilized for theproduction of colored negatives,

, reverse positives or in the negative positive process.

The following examples serve to further illustrate the invention but itis to be understood that the invention is not restricted thereto. Theparts are by weight unless otherwise stated.

Example 1 at -70 C. 30 parts of 1-hydroxy-2-naphthoyl chloride,

The benzene is removed by distillation at C. to C; over a period of 1hour. The reaction mixture is heated from 100 C. to C. over a period of1 hour, and maintained at 130- C. for 2 hours. To'the residue is addedat" 120 C.

250 parts ofglacial aceticacid. After heating at 115-120 C. for hour andcooling below 80 0., there are added v partsethanol or methanol. Themixture is cooled to 20 C. and agitated for 2 to 5 hours. After chillingat 0-5 G. for 1 hour, the crude product is collected on a filter, washedwith 200 parts of ethanol, sucked dry, then air dried.

The crude product is recrystallized, by dissolving it in a refluxingmixture of 350 parts of benzene, and I V I 150 parts of ethanol. Thesolution is filtered while hot to remove any insoluble material.

- -'I 'he'-. filtrate: is cooled"to;20?- C.., agitatedrfon /g hour andthen chilledaat .15? G. foa hour. crystalline product is collectedsonafilten, washed with: 125 parts of ethanol, sucked. drgr-randvthen airdried.

.5 gramv of. the resulting color former. is. added to-100 cc. of aphotogr-aphicsilverbromideemulsion- The: emulsion is. coated: on atransparent support and'dr-ied. After exposure; the. film is developedin a color forming developencompris; ingwater,

1000 parts of sodium sulfite,

parts of p-diethyl'amino aniline,

2:5: parts of sodium. carbonate. and:

70 parts of potassium bromide;

A silver dye. image is formed; After removal of the silver by bleachingin a potassium ferrocyani'd'e solution and subsequent-fixing adeeplycoloredfgreenisli blue dye imageremains, .said

dye. image being characterizedJby-an exceedingly fine. grain. I

Example 2 OisHir HSOr- This product is prepared by the same method usedin Example 1 but from 50 parts of3-amino-4-octadecylaminobenzenesulfonic acid,

500 parts of benzene,

30 parts of pyridine, and

42 parts of 1-hydroxy-4-chloro-2-naphthoyl o chloride.

When this color former is incorporated in a photographic silver halideemulsion, the emulsion coated on a support and exposed, developed andprocessed as in Example 1, beautiful cyan dye images of exceedingly finegrain are obtained.

Example 3 (lJuHu N OH use? AOJH To 250 parts of sulfuric acid (100%) at10 C. are added portionwise 50 parts of 1-0ctadecyl-2- (2-(l-hydroxy)naphthyl) benzimidazole-5- sulfonic acid.

The reaction mixture is agitated at 10-15" C. for 1 hour, then warmed to2025 C. and agitated until sulfonation is complete. After drowning in2000 parts of ice with agitation, there are added 1000 parts of water,and

300 parts of potassium chloride. The crude product is collected on afilter, washed with 10%\ K01 solution, and dried.

The product is purified by recrystallization from 500 parts of methanol.

This color former when used in photographic silver halide emulsionslikewise yields cyan dye images of excellent spectral properties andexceedingly fine grain.

IHSCII,

This induct isprepared i nth same finanner aslth4i'n'partsroffleamino... ziaicidii i 300 parts of pyridine, 110 parts ofbenzene, and 40 parts of l-(carbethoxy-hydroxy) -2-naphthoyl chloride.

This color former 'gives on color forming development with the developerof Example 1 cyan dye images of exceedingly fine grain.

JEmampZe S:

Penn

, .-.oleylaminobenz nesulic ic This product is prepared in the samemanner as that of Example 1 but from .50 parts of3-amino-4-oleylaminobenzenesulfonic acid, 350 parts of pyridine, 100parts of benzene, and 35 parts of l-hydroxy-l-chloro 2 naphthoylchloride.

Example 6 This product is prepared in the same manner as that of Example1 but from 44 parts of 3-amino-4-octadecylaminobenzenesulfonic acid, 450parts of benzene,

25 parts of pyridine, and

30 parts of beta-cresotinoyl chloride.

wherein R1 is a hydroxy aromatic radical, the hydroxy group beingnuclear attached, and said radical being linked to the benzimidazoleradical in ortho-position to said hydrox group, R2 is a 7 long aliphaticchain" capable of rendering said compound fast to diffusion in thephotographic emulsion and R3 .is a water solubilizing group.

2. A photographic silver halide emulsion containing as a color formerfor the cyan image the compound 1-octadecyl-2-(2'-(l'-hydroxy) naphthyl)benzimidazole-5-sulfonic acid.

3. The process of producing cyan dye images of V exceedingly,fine;.;grain in a photographic silver halide emulsion which comprisesexposing said emulsion and developing the same with a developer "ofp'-phenylenediamine type in the presence of a color former having thefollowing formula: V

wherein R1 is a hydroxy. aromatio radical, the

hydroxy group being nuclear attached, and said radical being linked tothe benzimidazole radical in ortho-position to said hydroxy group, R2 isa long aliphatic chain capable of rendering said compound fast todifiusion in the photographic emulsion and R3 is a water solubilizinggroup.

8 :34. Theprocess as defined in claim" 3 wherein said color former islocated in the emulsion.

5. The process of producing cyan dye images of exceedingly fine grainwhich comprises exposing a photographic silver halide emulsioncontaining as-a color former the compound 1- octadecyl-2-(2-(1-hydroxy)naphthyl) benzimidazole-5-su1fonic acid and developing the exposedemulsion with a developer of the p-phenyl-

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING AS A COLOR FORMERFOR THE CYAN THE COMPOUNDS OF THE FOLLOWING FORMULA: